Microcontroller Controlled High-Side Switch

This is a small circuit that I designed to switch a 12-V power source using an I/O pin of a 3.3V microcontroller. The important thing to note is the high-voltage non-inverted switching. Vin are the high-voltage that need to be switched and for 2N2907, it can be as high as 40V. V2 is the uC output around 3.3V.

Important design notes:

Maximum load on 2N2907 is 500mA. This defines the maximum base current using I_c = beta * I_b. The beta for 2N2907 for this load is around 100 which means: I_b = 500mA/100 = 5mA.